BLTI-265

Clearing stored preferences does not reset the button text



git-svn-id: https://source.sakaiproject.org/svn/basiclti/trunk@128955 66ffb92e-73f9-0310-93c1-f5514f145a0a
BLTI-263

Update the documentation.



git-svn-id: https://source.sakaiproject.org/svn/basiclti/trunk@128956 66ffb92e-73f9-0310-93c1-f5514f145a0a